/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.core.triggers;



import java.util.Arrays;



/**

 * Repeat a trigger, either until some condition is met or forever.

 *

 * <p>For example, to fire after the end of the window, and every time late data arrives:

 *

 * <pre>{@code

 * Repeatedly.forever(AfterWatermark.isPastEndOfWindow());

 * }</pre>

 *

 * <p>{@code Repeatedly.forever(someTrigger)} behaves like an infinite {@code

 * AfterEach.inOrder(someTrigger, someTrigger, someTrigger, ...)}.

 */

public class RepeatedlyStateMachine extends TriggerStateMachine {



  private static final int REPEATED = 0;



  /**

   * Create a composite trigger that repeatedly executes the trigger {@code repeated}, firing each

   * time it fires and ignoring any indications to finish.

   *

   * <p>Unless used with {@link TriggerStateMachine#orFinally} the composite trigger will never

   * finish.

   *

   * @param repeated the trigger to execute repeatedly.

   */

  public static RepeatedlyStateMachine forever(TriggerStateMachine repeated) {

    return new RepeatedlyStateMachine(repeated);

  }



  private RepeatedlyStateMachine(TriggerStateMachine repeated) {

    super(Arrays.asList(repeated));

  }



  @Override

  public void onElement(OnElementContext c) throws Exception {

    getRepeated(c).invokeOnElement(c);

  }



  @Override

  public void onMerge(OnMergeContext c) throws Exception {

    getRepeated(c).invokeOnMerge(c);

  }



  @Override

  public boolean shouldFire(TriggerStateMachine.TriggerContext context) throws Exception {

    return getRepeated(context).invokeShouldFire(context);

  }



  @Override

  public void onFire(TriggerContext context) throws Exception {

    getRepeated(context).invokeOnFire(context);



    if (context.trigger().isFinished(REPEATED)) {

      // Reset tree will recursively clear the finished bits, and invoke clear.

      context.forTrigger(getRepeated(context)).trigger().resetTree();

    }

  }



  @Override

  public String toString() {

    return String.format("Repeatedly.forever(%s)", subTriggers.get(REPEATED));

  }



  private ExecutableTriggerStateMachine getRepeated(TriggerContext context) {

    return context.trigger().subTrigger(REPEATED);

  }

}